Tag Archives: nature

MRSA superbug: a global concern

There is an increasing amount of news coverage on the superbug, which is also known as the methicillin-resistant Staphylococcus aureus (MRSA). But how much do you really know? Here, I will talk about the reason why we should be concerned about the spread.MRSA trend

The history of this bacteria, Staph. aureus, can be traced back to the Egyptian mummies, which historians had recovered pathological changes that are consistent with staphalococcal osteomyelitis. Staph. aureus can be found in 20% to 45% of normal healthy adults. In the hospital-associated cases, serious infection is often caused by the bleach of protection. For example, the skin barrier protection is disrupted after going through an invasive surgery, which allows the colonization of Staph. aureus in tissues.

The concern of MRSA grows as the healthcare community now faces with strains of Staph. aureus that are equipped with methicillin and vancomycin resistance genes.

If you look at the timeline (from Nature Magazine), shortly after the introduction of penicillin in the 1940s, some strains of Staph. aureus were already found to have penicillinase/resistance to penicillin. And if you look at when methicillin is introduced to treat Staph. aureus infection, you can see that methicillin resistant strains can be found shortly after the introduction. Typically, vancomycin is used as a last resort due to its toxicity. But the resistance of vancomycin is also emerging.

Are we running out of options to treat Staph. aureus infection? Not now. But if we don’t take action soon to accelerate the antibiotics discovery, we will run out of options when vancomycin resistant strains dominate.

Q&A: Why do birds fly in V formation?

Have you ever looked up the sky and wondered why birds tend to fly in V formation? A group of scientists have followed a group of Northern Ibises to study their flying positions and flapping dynamics. From their experimental data, they have found concrete data that support a longstanding theory that the purpose of V formation is to save energy.

Birds

The leading bird tends to have a faster heart rate compared to the trailing bird. What the data suggests is that the leading bird creates a wind vortex, which helps the trailing bird to stay in air without spending the same amount of energy. Thus, the trailing bird does not have to flap as hard, though the motion needs to be coordinated with the vortex to gain the upward momentum.

For those of you who are interested in more about this story, please click on this link to watch the video published in Nature.

http://www.nature.com.proxy.uchicago.edu/news/v-is-for-vortex-1.14507

Universal Flu Shot in Sight?

Influenza virus places a large burden on our society. It is estimated that the costs of everything related to influenza virus infection comes to about $87.1 billion US dollars in the United States. With the existing vaccination program against influenza virus, you may ask why there isn’t a “one size fits all” that can make us completely immune from influenza virus infection with a single vaccine. My parents have asked me that question a few weeks ago. The way how I explain it is through the use of umbrellas. Let’s say the virus carries a bright red umbrella. The immune system recognizes the red cloth on the umbrella and then mount an immune response against the red cloth. But next year, the virus mutates due to selective pressure. The virus now carries a blue umbrella. The immune system now has to go through all the processes from sensing the infection to getting rid of the infection, instead of recognizing the virus at the beginning of the infection. The current strategy that the scientists are trying to develop is the use of broadly neutralizing antibody. The broadly neutralizing antibody recognizes not the cloth of the umbrella, but the stalk of the umbrella which is common among all subtypes of influenza.

A  recent review article by Dr. Krammer and Dr. Palese from Mount Sinai has covered the challenge of this antibody in an elegant way. The real challenge behind the application of a broadly neutralizing antibody against influenza virus is that different age groups tend to have totally different exposure history to the subtypes of influenza virus. Children tend to be naive for influenza virus infection when adult are exposed to it multiple times. Furthermore, the elderly appears to mount a less effective response after a flu shot. Thus, the application of the broadly neutralizing antibody needs to be tested extensively in different age groups before rolling out.

“The initial cost of conducting these trials might seem high, but investment in universal influenza virus vaccine approaches might make it possible to overcome the threat of seasonal and pandemic influenza.”